Make your Extra Deck to have only 1 type of monsters to make sure that even if you don't gain Life Points by this card's effect, your opponent will not gain them either.
Use this card with "Bad Reaction to Simochi" activated, so if you don't gain 3000 Life Points, your opponent will take 3000 damage, at least.
If your Anti-Cure Deck doesn't rely on the Extra Deck, it may be a good idea not to use any Xyz or Synchro monsters at all, to ensure that your opponent will take the damage. If you fill your Extra Deck with Fusion monsters, this card could be superior to "Gift Card", as you could declare "Fusion" if "Bad Reaction to Simochi" is not on the field, gaining life points, and declaring "Xyz" or "Synchro" if it is, inflicting damage to your opponent.
You can use this card in your Side Deck and use it after you already know what your opponent is playing to more accurately use its effect.
Because Fusion Monsters are not very commonly played compared to Synchro and Xyz monsters, this card works best with Decks that rely on Fusion Monsters, such as "Elemental HEROes" and "Gem-Knights". This will mostly guarantee you gain 3000 LP.
Even outside of decks like this, if you think the Extra deck slots are worth it you can splash 2 Fusions (2 in case of the opponent running a Fusion for the purpose of Instant Fusion) into nearly anything for the same effect. If you are facing HEROS or Gem-knights, you can simply call Synchros or Xyzs as appropriate.
In a "Hope for Exodia" Deck, this card is a great choice in addition to the 3 "Gift Cards" for an even deeper draw power or being able to have an early big draw power.
It's best to run a single Fusion Monster so you can activate this card and have greater chance at letting your opponent gain 3000 LP as Fusion Monsters are not so common as already stated above.
Even if for some reason, you opponent does not have Synchro, XYZ Monsters but has Fusion Monsters only, your would be able to get your strategy work with your remaining copy(ies) of this card.
This card would also let you know a little more about your opponent strategy.